A three-dimensional scanning displacement platform

Abstract

This invention discloses a three-dimensional scanning displacement platform, comprising an electrostatically driven in-plane two-dimensional positioning platform, a piezoelectric actuation assembly, and a fixed frame. The piezoelectric actuation assembly includes an even number of piezoelectric actuation units, each formed by depositing a piezoelectric thin film on a silicon substrate. One end of each piezoelectric actuation unit is connected to the outer edge of the in-plane two-dimensional positioning platform, and the other end is connected to the inner edge of the fixed frame. The even number of piezoelectric actuation units are symmetrically arranged about the centerline of the in-plane two-dimensional positioning platform in a first direction and / or a second direction, wherein the first direction and the second direction are perpendicular to each other. The three-dimensional scanning displacement platform proposed in this invention exhibits non-coupled motion in each axial direction, solving the problem of crosstalk in three-dimensional motion, and can generate large displacement strokes in the out-of-plane direction.

Description

Technical Field

[0001] This invention relates to the field of precision positioning system technology, and in particular to a three-dimensional scanning displacement platform. Background Technology

[0002] With the development of micro-nano technology, multi-dimensional precision positioning systems occupy an important position in cutting-edge scientific research fields and are widely used in various fields such as precision measurement and semiconductor technology.

[0003] Currently, multi-dimensional piezoelectric ceramic displacement platforms are the mainstream positioning system, offering advantages such as fast response speed and large driving force. However, the magnitude of the displacement driven by piezoelectric ceramics is closely related to the thickness of the piezoelectric ceramic material, and multi-dimensional driving requires the superposition of multiple driving units, resulting in a large overall system size. On the other hand, among multi-dimensional displacement positioning platforms, three-dimensional positioning platforms have a wider range of applications than two-dimensional positioning platforms; however, their overall structure is more complex.

[0004] In comparison, electrostatic actuation offers advantages such as simple structure and ease of fabrication. Leveraging the ease and directness of vertical fabrication using micro / nano processes, research groups both domestically and internationally have reported on three-dimensional electrostatic actuation platforms. For example, Y. Ando et al. achieved in-plane to out-of-plane displacement conversion by constructing tilted leaf springs; however, the displacement conversion efficiency was low and crosstalk was severe. X. Liu et al. designed independent actuation units with in-plane comb teeth and out-of-plane parallel plates; however, motion coupling still existed, and the out-of-plane displacement stroke was small. K. Takahashi et al. achieved out-of-plane actuation by designing asymmetrical comb teeth; however, due to the limited space between the upper and lower comb teeth, the achievable displacement stroke remained small. Typically, three-dimensional electrostatic actuation platforms based on single-wafer fabrication struggle to overcome technical challenges such as in-plane and out-of-plane motion crosstalk and limited out-of-plane motion space.

[0005] The above background information is provided only to aid in understanding the concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a three-dimensional scanning displacement platform where the motion in each axial direction is non-coupled, thus solving the problem of crosstalk in three-dimensional motion and enabling large displacement strokes in out-of-plane directions.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention discloses a three-dimensional scanning displacement platform, including an electrostatically driven in-plane two-dimensional positioning platform, a piezoelectric actuation assembly, and a fixed frame. The piezoelectric actuation assembly includes an even number of piezoelectric actuation units, which are formed by depositing piezoelectric thin films on a silicon substrate. One end of each piezoelectric actuation unit is connected to the outer edge of the in-plane two-dimensional positioning platform, and the other end is connected to the inner edge of the fixed frame. The even number of piezoelectric actuation units are symmetrically arranged about the center lines of the in-plane two-dimensional positioning platform in a first direction and / or a second direction, wherein the first direction and the second direction are perpendicular to each other.

[0009] Preferably, the piezoelectric actuation unit includes one or more interconnected piezoelectric actuators, each piezoelectric actuator having a moving end and a fixed end. The moving end of the innermost piezoelectric actuator in each piezoelectric actuation unit is connected to the outer edge of the in-plane two-dimensional positioning platform, and the fixed end of the outermost piezoelectric actuator in each piezoelectric actuation unit is connected to the inner edge of the fixed frame.

[0010] Preferably, the piezoelectric actuator includes a device layer, an oxide layer, and a piezoelectric layer. The oxide layer is disposed between the device layer and the piezoelectric layer to electrically isolate the device layer and the piezoelectric layer. The device layer is made of monocrystalline silicon. The piezoelectric layer includes at least one piezoelectric thin film, which is spaced apart from each other. Each piezoelectric thin film is provided with an upper electrode and a lower electrode.

[0011] Preferably, the piezoelectric layer comprises 2N piezoelectric thin films, wherein the 2N piezoelectric thin films are equally divided into N groups, and the two piezoelectric thin films in each group are arranged in the same direction, where N is a positive integer, and most preferably, N = 4.

[0012] Preferably, the piezoelectric layer includes two piezoelectric thin films, the device layer has an "I" shaped structure, the two piezoelectric thin films are arranged along the length of the "I" shape, wherein the moving end and the fixed end are located on both sides of the same end of the "I" shape.

[0013] Preferably, the piezoelectric layer includes four piezoelectric thin films, the device layer is a U-shaped structure, the four piezoelectric thin films are respectively disposed on two sides of the U-shaped structure, and the two piezoelectric thin films disposed on the same side of the U-shaped structure are arranged in a direction parallel to the two sides of the U-shaped structure, wherein the moving end and the fixed end are respectively located at the two ends of the U-shaped structure.

[0014] Preferably, the piezoelectric layer includes eight piezoelectric thin film pieces. The device layer is composed of two symmetrically connected U-shaped structures to form a "square" shape. Four of the piezoelectric thin film pieces are respectively arranged on each U-shaped structure. The four piezoelectric thin film pieces are respectively arranged on both sides of the U-shaped structure in pairs, and the two piezoelectric thin film pieces arranged on the same side of the U-shaped structure are arranged along the direction parallel to the two sides of the U-shaped structure. Among them, the moving end and the fixed end are respectively located at the two ends where the two U-shaped structures are connected.

[0015] Preferably, the outer frame of the in-plane two-dimensional positioning platform is in a rectangular structure, and at least one piezoelectric actuating unit is respectively connected at the four sides or the opposite two sides of the rectangular structure, and at least one piezoelectric actuating unit connected to each side is symmetrically arranged.

[0016] Preferably, one piezoelectric actuating unit is respectively connected at each side of the rectangular structure, and the piezoelectric actuating units on each side are respectively connected at the midpoints of each side.

[0017] Preferably, the in-plane two-dimensional positioning platform includes an outer frame, an inner frame, a displacement stage, a first elastic unit, a second elastic unit, a first comb tooth unit and a second comb tooth unit. The outer frame supports the inner frame through the first elastic unit so that the outer frame can drive the inner frame in the first direction. The inner frame supports the displacement stage through the second elastic unit so that the inner frame can drive the displacement stage in the second direction. The fixed comb tooth part of the first comb tooth unit is fixedly connected to the outer frame, and the movable comb tooth part of the first comb tooth unit is fixedly connected to the inner frame. The fixed comb tooth part of the second comb tooth unit is fixedly connected to the inner frame, and the movable comb tooth part of the second comb tooth unit is fixedly connected to the displacement stage.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The three-dimensional scanning displacement platform proposed by the present invention adopts a combination of electrostatic drive and piezoelectric drive. The in-plane two-dimensional positioning platform adopts an electrostatic drive type, and an even number of piezoelectric actuating units are symmetrically arranged on the in-plane two-dimensional positioning platform, ensuring that the out-of-plane displacements of each piezoelectric actuator are the same, thereby giving the three-dimensional scanning displacement platform a displacement without crosstalk in the Z-axis direction. Moreover, due to the different Young's moduli and strain mismatches between the piezoelectric thin film and the silicon substrate of the piezoelectric actuating unit, a tip displacement is generated, enabling a large displacement stroke in the out-of-plane direction, overcoming the problem of small Z-axis displacement of the three-dimensional scanning displacement platform. In addition, the overall three-dimensional drive platform structure has an integrated structure. The in-plane two-dimensional positioning platform can use a silicon substrate, and the piezoelectric actuating unit also uses a silicon substrate. Therefore, it can be realized through silicon-based integrated processing, greatly reducing the complexity of processing the overall structure.

[0019] In a further embodiment, the present invention also has the following beneficial effects:

[0020] By arranging two piezoelectric thin films along their length, opposite voltages can be applied to the two films, ensuring the moving end remains horizontal. Furthermore, by arranging four piezoelectric thin films in a U-shape, with each pair positioned on opposite sides of the U, opposite voltages can be applied to each pair of the four films. This not only ensures the moving end remains horizontal but also prevents lateral displacement of the moving end near the fixed end during upward bending. Even further, arranging eight piezoelectric thin films in a symmetrical U-shape further enhances the structural stability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a three-dimensional scanning displacement platform according to a preferred embodiment of the present invention;

[0022] Figure 2 yes Figure 1 A schematic diagram of the structure of the in-plane two-dimensional positioning platform;

[0023] Figure 3 yes Figure 1 A cross-sectional schematic diagram of the piezoelectric actuator in the diagram;

[0024] Figure 4 yes Figure 1 A schematic diagram of the structure of the piezoelectric actuator in the diagram;

[0025] Figure 5 yes Figure 4 Simulation results of displacement drive of piezoelectric actuator in the image;

[0026] Figures 6a to 6c These are the driving situations of the three-dimensional scanning displacement platform in different directions according to the preferred embodiment of the present invention. Detailed Implementation

[0027] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0028] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to that other component. Furthermore, a connection can be used for both fixing and circuit / signal connectivity.

[0029] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0031] This invention, in a preferred embodiment, proposes a structure for a three-dimensional scanning displacement platform with in-plane electrostatic actuation and out-of-plane piezoelectric actuation. By driving an in-plane electrostatic actuation two-dimensional platform unit with an out-of-plane piezoelectric actuation unit, uncoupled motion and large displacement in three dimensions can be achieved. Specifically, the in-plane electrostatic actuation two-dimensional scanning platform unit provides uncoupled motion and large displacement in two dimensions; the out-of-plane piezoelectric actuation unit utilizes the difference in Young's modulus between the piezoelectric film and the silicon substrate, resulting in strain mismatch and generating tip displacement (i.e., displacement at the moving end), enabling large displacement in the out-of-plane direction. Furthermore, the overall three-dimensional driving platform structure features an integrated design, which can be achieved through integrated silicon-based fabrication, significantly reducing the complexity of the overall structure fabrication.

[0032] like Figure 1 As shown, a preferred embodiment of the present invention discloses a three-dimensional scanning displacement platform, which is a miniature three-dimensional scanning displacement platform that combines an in-plane decoupled electrostatic comb drive method and an out-of-plane piezoelectric thin film drive method. It includes three parts: an in-plane two-dimensional positioning platform 100, a piezoelectric actuation component 200, and a fixed frame 300. The overall structure of this three-dimensional scanning displacement platform is fabricated on a silicon-on-insulator (SOI) substrate. A piezoelectric thin film layer is deposited on the device layer to further construct a Z-axis actuator, forming the piezoelectric actuation component. A silicon dioxide layer is deposited between the piezoelectric thin film layer and the device layer to achieve electrical insulation. The in-plane electrostatic drive two-dimensional positioning platform and the out-of-plane piezoelectric thin film actuator will be described separately below.

[0033] Combination Figure 2The in-plane two-dimensional positioning platform 100 (i.e., the XY two-dimensional platform) adopts a frame-in-frame structure, comprising an outer fixed frame (referred to as outer frame 10), an inner movable frame (referred to as inner frame 20), and a central displacement stage 30. During in-plane movement, the outer frame 10 remains fixed, while the inner frame 20 is freely movable. The support spring structure adopts a folded-flexure spring structure, possessing a high spring stiffness ratio, which can effectively overcome the lateral instability of the moving comb teeth and effectively increase the maximum displacement stroke. The outer frame 10 supports the inner frame 20 through two external support springs 51, and the central displacement stage 30 is connected to and supported by the inner frame 20 through an internal support spring 52. Each comb tooth group includes a fixed comb tooth and a movable comb tooth. The fixed comb tooth is connected to an external voltage and remains fixed to its frame; the movable comb tooth is grounded and subjected to electrostatic force with the fixed comb tooth, causing the comb tooth structure to displace in the corresponding direction. The outer frame includes the fixed comb teeth of the first comb tooth group 41 and the third comb tooth group 43, which drive the inner frame 20 along the ±X-axis directions respectively. The inner frame 20 includes the fixed comb teeth of the second comb tooth group 42 and the fourth comb tooth group 44, which drive the displacement stage 30 along the ±Y-axis directions respectively. Therefore, this structural design enables the displacement stage 30 to achieve decoupling of its motion mechanism along the X and Y directions, ensuring in-plane motion decoupling. The shape of the displacement stage 30 can be set according to actual conditions without affecting its motion, and the number of comb teeth in each comb tooth group can be set to adjust different displacement strokes.

[0034] Specifically, the electrostatic comb-driven low-crosstalk in-plane two-dimensional positioning platform 100 includes an outer frame 10, an inner frame 20, a displacement stage 30, a first elastic unit, a second elastic unit, a first comb unit, and a second comb unit. The outer frame 10 supports the inner frame 20 through the first elastic unit, enabling the outer frame 10 to drive the inner frame 20 along a first direction. The inner frame 20 supports the displacement stage 30 through the second elastic unit, enabling the inner frame 20 to drive the displacement stage 30 along a second direction. The fixed comb teeth of the first comb unit are fixedly connected to the outer frame 10, and the movable comb teeth of the first comb unit are fixedly connected to the inner frame 20. The fixed comb teeth of the second comb unit are fixedly connected to the inner frame 20, and the movable comb teeth of the second comb unit are fixedly connected to the displacement stage 30. In this embodiment, the first direction is the X-axis direction, and the second direction is the Y-axis direction, that is, the first direction and the second direction are perpendicular to each other. The first comb unit includes a first comb tooth group 41 and a third comb tooth group 43. The fixed comb tooth portions of the first comb tooth group 41 and the third comb tooth group 43 are respectively fixedly connected to the inner walls of the two sides of the outer frame 10 along the Y-axis direction. The movable comb tooth portion of the first comb tooth group 41 is fixedly connected to the side wall of the inner frame 20 opposite to the fixed comb tooth portion of the first comb tooth group 41. The movable comb tooth portion of the third comb tooth group 43 is fixedly connected to the side wall of the inner frame 20 opposite to the fixed comb tooth portion of the third comb tooth group 43. The second comb unit includes a second comb tooth group 42 and a fourth comb tooth group 44. The fixed comb tooth portions of the second comb tooth group 42 and the fourth comb tooth group 44 are respectively fixedly connected to the inner walls of the two sides of the inner frame 20 along the X-axis direction. The movable comb tooth portion of the second comb tooth group 42 is fixedly connected to the side wall of the displacement stage 30 opposite to the fixed comb tooth portion of the second comb tooth group 42. The movable comb tooth portion of the fourth comb tooth group 44 is fixedly connected to the side wall of the displacement stage 30 opposite to the fixed comb tooth portion of the fourth comb tooth group 44.

[0035] The first elastic unit includes two external support springs 51. Each external support spring 51 includes four first flexible rods arranged along the Y-axis. The outer ends of the four first flexible rods are connected by multiple first connectors. The inner ends of some of the first flexible rods are connected to the outer frame 10, and the inner ends of the other two first flexible rods are connected to the inner frame 20. In this embodiment, the inner ends of the first flexible rods located on both sides are connected to the outer frame 10, and the inner ends of the first flexible rod located in the middle are connected to the inner frame 20. The second elastic unit includes an internal support spring 52. The internal support spring 52 includes four second flexible rods arranged along the X-axis. The inner ends of the four second flexible rods are connected by multiple second connectors. The outer ends of some of the second flexible rods are connected to the inner frame 20, and the outer ends of the other two second flexible rods are connected to the moving platform 30. In this embodiment, the outer ends of the second flexible rod located in the middle are connected to the inner frame 20, and the outer ends of the second flexible rods located on both sides are connected to the moving platform 30. The aforementioned external support spring 51 and internal support spring 52 are both folded-flexure spring structures. The external support spring 51 has four flexible rod ends fixed on the outside of the spring to support the inner frame, while the internal support spring 52 has four flexible rod ends fixed in the middle of the spring to support the displacement stage. These two support spring layouts can effectively overcome the lateral instability of the moving comb teeth and effectively increase the maximum displacement stroke.

[0036] In this in-plane two-dimensional positioning platform, the outer frame 10, inner frame 20, and displacement stage 30 are respectively made of silicon-on-insulator (SiI). The SiI includes a device layer made of silicon, an oxide layer made of silicon dioxide, and a substrate layer made of silicon, arranged from top to bottom. The outer frame 10 includes a device layer, an oxide layer, and a substrate layer. The inner frame 20 includes a device layer, at least a partial oxide layer, and at least a partial substrate layer. The displacement stage 30 includes a device layer. In addition, the fixed frame 300 also includes a device layer, an oxide layer, and a substrate layer. A ground electrode and multiple driving electrodes are provided on the device layer of the fixed frame 300. The number of driving electrodes corresponds to the sum of the number of comb teeth in the first comb unit and the second comb unit. A first insulating gap is provided in the device layer of the fixed frame 300 so that each driving electrode is electrically insulated.

[0037] The piezoelectric actuation assembly 200 includes an even number of piezoelectric actuation units 210. One end of each piezoelectric actuation unit 210 is connected to the outer edge of the outer frame 10 of the in-plane two-dimensional positioning platform 100, and the other end is connected to the inner edge of the fixed frame 300. The even number of piezoelectric actuation units 210 are symmetrically arranged about the center lines of the in-plane two-dimensional positioning platform 100 in the X-axis and / or Y-axis directions. Further, the outer frame 10 of the in-plane two-dimensional positioning platform 100 has a rectangular structure. At least one piezoelectric actuation unit 210 is connected to each of the four sides of the rectangular structure or to two opposite sides, and the at least one piezoelectric actuation unit 210 connected to each side is symmetrically arranged. In this specific embodiment, one piezoelectric actuation unit 210 is connected to each side of the rectangular structure (a total of four piezoelectric actuation units 210), and the piezoelectric actuation units 210 on each side are connected to the midpoint of each side.

[0038] The piezoelectric actuation unit 210 includes one or more piezoelectric actuators 211 connected to each other. The piezoelectric actuator 211 is provided with a moving end 2111 and a fixed end 2112. When the piezoelectric actuation unit 210 includes a piezoelectric actuator 211, the moving end 2111 of the piezoelectric actuator 211 is connected to the outer edge of the outer frame 10 of the in-plane two-dimensional positioning platform 100, and the fixed end 2112 of the piezoelectric actuator 211 is connected to the inner edge of the fixed frame 300. When the piezoelectric actuation unit 210 includes multiple piezoelectric actuators 211, the moving ends 21111 and fixed ends 2112 of two adjacent piezoelectric actuators 211 are connected, and the moving end 2111 of the innermost piezoelectric actuator 211 in the piezoelectric actuation unit 210 is connected to the outer edge of the outer frame 10 of the in-plane two-dimensional positioning platform 100, and the fixed end 2112 of the outermost piezoelectric actuator 211 in the piezoelectric actuation unit 210 is connected to the inner edge of the fixed frame 300.

[0039] like Figure 3 The piezoelectric actuator 211 includes a device layer 2113, an oxide layer 2114, and a piezoelectric layer 2115. The oxide layer 2114 is disposed between the device layer 2113 and the piezoelectric layer 2115 to electrically isolate them. The piezoelectric layer 2115 includes at least one piezoelectric thin film 2116, which are spaced apart from each other. Each piezoelectric thin film 2116 has an upper electrode 2117 and a lower electrode 2118. Specifically, the device layer 2113 is made of monocrystalline silicon, and the oxide layer 2114 is made of silicon dioxide. When a positive voltage is applied to the piezoelectric layer 2115, a strain mismatch occurs due to the difference in Young's modulus between the piezoelectric layer 2115 and the device layer 2113, resulting in upward displacement at the end and also lateral displacement.

[0040] like Figure 4, the piezoelectric layer 2115 includes eight piezoelectric thin film pieces 2116 (the first piezoelectric thin film piece 61, the second piezoelectric thin film piece 62, the third piezoelectric thin film piece 63, the fourth piezoelectric thin film piece 64, the fifth piezoelectric thin film piece 65, the sixth piezoelectric thin film piece 66, the seventh piezoelectric thin film piece 67, and the eighth piezoelectric thin film piece 68 respectively). The device layer 2113 consists of two symmetrically connected U-shaped structures to form a "square" shape. Four piezoelectric thin film pieces 2116 are respectively arranged on each U-shaped structure. The four piezoelectric thin film pieces 2116 are pairwise arranged on both sides of the U-shaped structure, and the two piezoelectric thin film pieces 2116 arranged on the same side of the U-shaped structure are arranged along the direction parallel to the two sides of the U-shaped structure. Among them, the moving end 2111 and the fixed end 2112 are respectively located at the two ends where the two U-shaped structures are connected. With this structure, the lateral displacement can be eliminated and the stroke of the piezoelectric actuator in the Z-axis can be enlarged.

[0041] Combined Figure 4 with Figure 5 , eight piezoelectric thin film pieces 2116 are symmetrically tiled on the piezoelectric actuator 211. A positive voltage is applied to the upper electrodes of the first piezoelectric thin film piece 61, the third piezoelectric thin film piece 63, the fifth piezoelectric thin film piece 65, and the seventh piezoelectric thin film piece 67, and the lower electrodes of the second piezoelectric thin film piece 62, the fourth piezoelectric thin film piece 64, the sixth piezoelectric thin film piece 66, and the eighth piezoelectric thin film piece 68. The lower electrodes of the first piezoelectric thin film piece 61, the third piezoelectric thin film piece 63, the fifth piezoelectric thin film piece 65, and the seventh piezoelectric thin film piece 67 and the upper electrodes of the second piezoelectric thin film piece 62, the fourth piezoelectric thin film piece 64, the sixth piezoelectric thin film piece 66, and the eighth piezoelectric thin film piece 68 are grounded, which can generate Figure 5 the out-of-plane displacement shown in. The gap between each piezoelectric thin film piece 2116 and the frame of the single-crystalline silicon device layer 2113 is used for wiring, and there is a gap between each piezoelectric thin film piece 2116 to isolate two adjacent piezoelectric thin film pieces 2116.

[0042] In this specific embodiment, a piezoelectric actuator 211 is respectively connected to the midpoints of the four sides of the outer frame 10 of the in-plane two-dimensional positioning platform 100. Each piezoelectric actuator 211 is connected to the same positive voltage, which can ensure that the Z-axis displacements of each connection point are the same, causing the in-plane two-dimensional positioning platform 100 to generate an out-of-plane displacement. The structure of the piezoelectric actuator 211 with the above-mentioned eight symmetrically tiled piezoelectric thin film pieces 2116 is adopted. Among them, the U-shaped structure arrangement can offset the lateral displacement of the moving end 2111 and enlarge the displacement stroke in the Z-axis. The symmetric U-shaped structure arrangement is more stable than the single-sided U-shaped structure.

[0043] Driving each axis direction of the three-dimensional scanning displacement platform of this embodiment, the driving conditions in different directions are obtained as shown in Figures 6a to 6c shown. It can be seen from Figure 6a that when driving in the Z-axis direction, the displacements in the X-axis and Y-axis directions remain unchanged. From Figure 6b As can be seen, when driving in the X-axis direction, the displacement in the Y-axis and Z-axis directions remains unchanged. Figure 6c As can be seen, when driving in the Y-axis direction, the displacement in the X-axis and Z-axis directions remains unchanged. Therefore, the motion of the three-dimensional scanning displacement platform in each axis direction provided in this embodiment is uncoupled.

[0044] The preferred embodiment of this invention provides a three-dimensional scanning displacement platform in which out-of-plane motion (driven by four piezoelectric actuators) and in-plane motion (driven by four electrostatic comb teeth of the XY-axis two-dimensional platform) are decoupled. That is, out-of-plane motion does not change the in-plane displacement, and in-plane motion does not cause changes in out-of-plane displacement. This design uses piezoelectric drive for out-of-plane displacement, solving the problem of insufficient displacement in similar designs. The four-point support ensures that the displacement stage does not tilt. Simultaneously, the use of electrostatic comb teeth drive and a decoupled structure for in-plane motion achieves advantages such as fast response, low power consumption, and low-temperature operation, fully leveraging the advantages of each component to obtain three-dimensional uncoupled motion.

[0045] The structures of several other embodiments of piezoelectric actuators are also described below.

[0046] In some embodiments, only one piezoelectric film is present on each piezoelectric actuator, which is equivalent to simply retaining... Figure 4 The fifth piezoelectric film 65 has a moving end and a fixed end respectively located on both sides of the same end of the fifth piezoelectric film 65; however, when a voltage is applied to the fifth piezoelectric film 65, there may be a problem that the moving end is not horizontal, and the moving end will have a lateral displacement close to the fixed end when bending upward.

[0047] In some embodiments, only two piezoelectric films are present on each piezoelectric actuator, which is equivalent to simply retaining... Figure 4 The fifth piezoelectric film 65 and the sixth piezoelectric film 66 (equivalent to a device layer with an "I" shaped structure) have their moving end and fixed end respectively located on both sides of the same end of the fifth piezoelectric film 65. When a positive voltage is applied to the fifth piezoelectric film 65 and a reverse voltage of the same value is applied to the sixth piezoelectric film 66, an S-shape is formed, which can ensure that the moving end is horizontal. However, there is still a problem that the moving end will have a lateral displacement close to the fixed end when bending upward.

[0048] In some embodiments, only four piezoelectric films are present on each piezoelectric actuator, which is equivalent to simply retaining... Figure 4 The fifth piezoelectric thin film 65, the sixth piezoelectric thin film 66, the seventh piezoelectric thin film 67, and the eighth piezoelectric thin film 68 (equivalent to a single U-shaped structure for the device layer), the positions of the moving end and the fixed end and Figure 4Similarly, at this time, a positive voltage is applied to the fifth piezoelectric film 65 and the seventh piezoelectric film 67, and a reverse voltage of the same value is applied to the sixth piezoelectric film 66 and the eighth piezoelectric film 68, forming a double S-shape. This not only ensures that the moving end is horizontal, but also avoids the problem of lateral displacement of the moving end near the fixed end when bending upwards. The preferred embodiment described above, based on this embodiment, uses two symmetrically connected U-shaped structures to form a symmetrical double S-shape, which can further improve the stability of the structure.

[0049] This invention provides a structure for a three-dimensional positioning platform based on a combination of electrostatic comb drive and piezoelectric drive, clarifying the decoupled nature of the motion mechanism. The electrostatic comb drive provides in-plane displacement, offering advantages such as high-precision positioning and fast response speed, enabling accurate in-plane positioning. The use of a folded-flexure spring with a high spring stiffness ratio as the support spring for this positioning platform overcomes the lateral instability of the moving comb teeth, effectively increasing the maximum displacement stroke. The piezoelectric drive provides out-of-plane displacement, offering advantages such as stable motion, large stroke, and ease of manufacturing, extending the positioning platform from two-dimensional to three-dimensional, and ensuring no crosstalk between the three-axis drive displacements, thus expanding the application range of the positioning platform.

[0050] The background section of this invention may include background information about the problems or circumstances surrounding the invention, rather than a description of prior art by others. Therefore, the content included in the background section is not an admission of prior art by the applicant.

[0051] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate different embodiments or examples and features of different embodiments or examples described in this specification without contradiction. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope defined by the appended claims.

Claims

1. A three-dimensional scanning displacement platform, characterized by, The application relates to a static driving in-plane two-dimensional positioning platform, a piezoelectric actuating assembly and a fixed frame, wherein the piezoelectric actuating assembly comprises an even number of piezoelectric actuating units formed by arranging piezoelectric film pieces on a silicon substrate, one end of each piezoelectric actuating unit is connected to the outer edge of the in-plane two-dimensional positioning platform, the other end is connected to the inner edge of the fixed frame, and the even number of piezoelectric actuating units are arranged in the center line of the in-plane two-dimensional positioning platform in a first direction and / or a second direction, the first direction and the second direction are perpendicular to each other; the piezoelectric actuating unit comprises one piezoelectric actuator or a plurality of piezoelectric actuators connected to each other, the piezoelectric actuator is provided with a moving end and a fixed end, wherein the moving end of the innermost piezoelectric actuator in each piezoelectric actuating unit is connected to the outer edge of the in-plane two-dimensional positioning platform, and the fixed end of the outermost piezoelectric actuator in each piezoelectric actuating unit is connected to the inner edge of the fixed frame.

2. The three-dimensional scanning displacement platform of claim 1, wherein, The piezoelectric actuator comprises a device layer, an oxidation layer and a piezoelectric layer, the oxidation layer is arranged between the device layer and the piezoelectric layer for electrically insulating the device layer and the piezoelectric layer, wherein the device layer adopts monocrystalline silicon, the piezoelectric layer comprises at least one piezoelectric film piece, each piezoelectric film piece is arranged separately, and each piezoelectric film piece is respectively provided with an upper electrode and a lower electrode.

3. The three-dimensional scanning displacement platform of claim 2, wherein, The piezoelectric layer comprises 2N piezoelectric film pieces, wherein the 2N piezoelectric film pieces are equally divided into N groups, two piezoelectric film pieces in each group are arranged in the same direction, and N is a positive integer.

4. The three-dimensional scanning displacement platform of claim 2, wherein, The piezoelectric layer comprises two piezoelectric film pieces, the device layer is in a "I" shape structure, and the two piezoelectric film pieces are arranged in the length direction of the "I" shape structure, wherein the moving end and the fixed end are arranged at the two sides of the same end of the "I" shape structure.

5. The three-dimensional scanning displacement platform of claim 2, wherein, The piezoelectric layer comprises four piezoelectric film pieces, the device layer is in a U-shaped structure, and the four piezoelectric film pieces are arranged on the two side edges of the U-shaped structure in pairs, and the two piezoelectric film pieces arranged on the same side edge of the U-shaped structure are arranged in the direction parallel to the two side edges of the U-shaped structure, wherein the moving end and the fixed end are respectively located at the two end heads of the U-shaped structure.

6. The three-dimensional scanning displacement platform of claim 2, wherein, The piezoelectric layer comprises eight piezoelectric film pieces, the device layer is composed of two symmetrically connected U-shaped structures to form a "mouth" shape, wherein four piezoelectric film pieces are arranged on each U-shaped structure, the four piezoelectric film pieces are arranged on the two side edges of the U-shaped structure in pairs, and the two piezoelectric film pieces arranged on the same side edge of the U-shaped structure are arranged in the direction parallel to the two side edges of the U-shaped structure, wherein the moving end and the fixed end are respectively located at the two end heads of the two U-shaped structures connected to each other.

7. The three-dimensional scanning displacement platform of claim 1, wherein, The outer frame of the in-plane two-dimensional positioning platform is in a rectangular structure, at least one piezoelectric actuating unit is connected to each of the four edges of the rectangular structure or to opposite two edges, and the at least one piezoelectric actuating unit connected to each edge is symmetrically arranged.

8. The three-dimensional scanning displacement platform of claim 7, wherein, A piezoelectric actuating unit is connected to each side of the rectangular structure, and the piezoelectric actuating units on each side are connected to the midpoint of each side.

9. The three-dimensional scanning displacement platform according to any one of claims 1 to 8, characterized in that, The in-plane two-dimensional positioning platform comprises an outer frame, an inner frame, a displacement table, a first elastic unit, a second elastic unit, a first comb tooth unit and a second comb tooth unit, wherein the outer frame supports the inner frame through the first elastic unit so that the outer frame can drive the inner frame in a first direction, the inner frame supports the displacement table through the second elastic unit so that the inner frame can drive the displacement table in a second direction, the fixed comb tooth part of the first comb tooth unit is fixedly connected to the outer frame, the movable comb tooth part of the first comb tooth unit is fixedly connected to the inner frame, the fixed comb tooth part of the second comb tooth unit is fixedly connected to the inner frame, and the movable comb tooth part of the second comb tooth unit is fixedly connected to the displacement table.

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